Figure 4.

Downregulation of miR-125b enhances the sensitivity of U87 cells to TMZ. U87 cells were transfected with NC-DP, 125b-DP or 125b-AS, respectively. After incubation for 48 h, the cells were treated with TMZ. (A) Observation of cell morphology. After being treated with TMZ, the cells were incubated for another 24 h and cell morphology was examined under a microscrope. (B) Determination of cell proliferation rate using MTT assay. U87 cells were transfected with oligonucleotides and TMZ were added into the cell culture medium. After being cultured for 24 h, the cell proliferation rates were evaluated by MTT assay. The inhibitory rates of cells were calculated using the formula: (OD value in 0.1% DMSO-treated group−OD value in TMZ and oligonucleotide treated group/OD value in 0.1% DMSO-treated group × 100%. Statistically significant differences between the groups of 125b-DP+TMZ and NC-DP+TMZ or between 125b-AS+TMZ and NC-DP+TMZ group were observed: *P<0.05 (P=0.0216) and **P<0.01 (P=0.0043). (C) Observation of nuclear morphology. Cells were stained with Hoechst 33342 and nuclear morphology was observed under a fluorescence microscope. The white arrows show the apoptotic cells with condensed, fragmented nuclei. (D) Quantities of the apoptosis cells with Annexin V-FITC/PI stain and Flow cytometry analysis. Early apoptotic cells (Annexin V+/PI−) are in the right lower quadrant.